Definition of "slumbrous"

Night is worn, / And the morn / Rises from the slumbrous mass.

1794, William Blake, Introduction (Songs of Experience), lines 13-14-15

When she had entered his employment a few days before, he had noticed, of course, that she had a sort of ethereal beauty; but then every girl you see in Hollywood has either ethereal beauty or roguish gaminerie or a dark, slumbrous face that hints at hidden passion.

1935, P. G. Wodehouse, 'Blandings Castle', Herbert Jenkins, 1957, page 179.